Potato-grader.



UNITED sTATEs PATENT oEEioE.

HANS PETERSON, 0F MORA, MINNESOTA..

POTATO-GRADER.

To all whom it may concern:

Be it known that I, HANS PETERSON, a citizen ofthe United States, residing at Mora, in the county of Kanabec and State of Minnesota, have invented certain new and useful Improvements in Potato-Graders; and I do hereby declare the following to be a full, clear, and eXact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to rotary screens for sorting vegetables and fruit; and it consists in the novel construction and combination of t-he parts hereinafter fully described and claimed.

In the drawings, Figure 1 is a longitudinal section through a screen constructed according to this invention. Fig. 2 is an end' view of the screen. Fig. 3 is a diagram of the screening cylinders.

A isa supporting frame of any approved construction provided with bearings o at its ends.

B-is a shaft arranged in a substantially horizontal position and ournaled in the bearings o. This shaft is provided at one end with a crank-handle b o-r any other suitable driving device for revolving it.

C, D, and E, are three screening cylinders arranged one inside the other and secured to the shaft B by arms f. These cylinders are formed of crossed wires, and the periphery of each cylinder is corrugated spirally to form screwthreads. Each screen has screwthreads which cover its entire surface, and the screwthreads are preferably of double pitch so as to have greater angularity than single-pitch screwthreads. The inner. and smallest cylinder C has the largest spaces between its wires, and its screWt-hreads c are arranged in the same direction as the screwthreads d of the intermediate cylinder D which has smaller spaces between its wires. The outer cylinder E has its screwthreads e arranged in the reverse direction from the screwthreads 0 and d, and its wires form space of still smaller size.

G is the inlet hopper into which the potatoes are placed and which discharges them into one end of the smallest screening cylinder C. The Ascrewthreads c cause the largest potatoes to move longitudinally of the screen and pass out by the discharge chute g at the other end of it from the hopper G.

The potatoes which fall through the Specification of Letters Patent.

Application led September 27, 1909.

Patented June 21, 1910.

serial No. 519,819.

screening cylinder C are caught by the intermediate screening cylinder D and are moved longitudinally by its screwthreads, the potatoes of intermediate size being discharged down a chute 7L arranged under the chute g. The potatoes which fall through the cylinder D are caught by the outer cylinder E and are moved longitudinally by its screwthreads e. The smallest potatoes are discharged from the cylinder E do-wn a chute z' arranged under the inlet hopper Gr, and the dirt falls through the wires of the largest screen E.

By making one of the screening cylinders with its screwthreads in the opposite direction from the screwthreads of the other two cylinders, the machine can be made shorter and more effective than if the screwthreads all ran in the same direction; and as the potatoes are discharged at opposite ends of the machine there is more room for the discharge chutes and receiving receptacles. By making the two inner cylinders with screwthreads of the same direction the potatoes discharged from them can be received in separate receptacles, or they can be received in a single receptacle when it is desirable to separate the potatoes into two grades only, and remove the smallest from them.

What I claim is:

l. In a grader, the combination, with a supporting frame, of a shaft journaled in the said frame and provided with sup ort's, and three screening cylinders of di erent diameter secured to the said supports and having their peripheries corrugated to form spiral screwthreads, one of the said cylinders having its screwthreads arranged in the opposite direction from the screwthreads of. the other two cylinders.

2. Ina grader, the combination, with a supporting frame, of three revoluble screening cylinders of diii'erent diameter mounted in the frame one inside the other and having their peripheriescorrugated to form spiral screwthreads, the outer cylinder havin its screwthreads arranged in the opposite direction from the screwthreads of the other two cylinders.

In testimony whereof I have aflixed my signature in the presence of two witnesses.

' I HANS PETERSON.

Witnesses:

A. O. BERGMAN, ALFRED V. SANDER. 

